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Worms in cats and dogs

In the UK your pet can become infected by roundworms, tapeworms, hookworms, whipworms and lungworms and unless you treat your pet regularly worms are difficult to avoid.

Adult worms vary dramatically in size from 2 mm long, to a scary 5 metres long! They generally live in your pet's gut, feeding off the contents. However, some (for instance whipworms) attach themselves to the gut wall to feed on the pet's blood.

It is important that you are aware that the roundworm can be spread to humans. This is not something you should be unduly worried about, but it is another significant reason why, as a responsible pet owner, you should worm your pet regularly.

What are the Symptoms?

As you can imagine, left untreated they can cause your cat or dog lots of discomfort and all sorts of health problems such as vomiting, diarrhoea, weight loss, anaemia and in some cases blindness.

However, with regular worming treatments, as recommended by your vet, these problems can all be avoided.


As well as causing problems for our pets, some worms, in particular the Toxocara roundworm, can be transmitted to humans. In rare cases this can cause problems such as blindness in both adults and children, with children being most at risk.

For this reason the British Small Animal Veterinary Association (BSAVA) now strongly recommends that we give your pet a lifestyle assessment and recommends monthly worming (especially if you have children) where the risk is high.

Roundworms are spaghetti-like in appearance and shed thousands of tiny eggs that are passed in the faeces of an infected animal - which is why it is so important to poop scoop. These eggs can survive in the soil for up to 2 years! Meanwhile another dog or cat can come along, pick them up on their paws, muzzle or fur, bring them into the home and/or swallow them whilst grooming!

It's worth mentioning that Roundworms eggs are microscopic in size and almost impossible to see with the naked eye. Even if you can't see worms in your pet's faeces, it may still have Roundworms. 

Puppies are usually born with roundworms and we always stress the importance of treating both mother and puppies more frequently whilst they are young.


A tapeworm's body is made up of segments, and each of these segments contains lots of eggs. As the worm matures in the intestines of the pet, the segments break off and are passed into the environment through the pet's faeces. You may see what looks like a grain of rice under your pet's tail.

Unlike roundworms, tapeworms cannot be passed directly from one pet to another, but need an intermediate host such as a flea, a bird or a small mammal.

The pet picks up the tapeworm infection following the ingestion of these intermediate hosts and so pets that hunt, eat a raw meat diet or have flea infestations are particularly at risk.

The flea tapeworm is the most common in both cats and dogs and is spread when a pet swallows an infected flea or louse whilst grooming. For this reason we strongly recommend eliminating fleas as an important part of worm control.


Lungworms are carried by garden slugs and snails and dogs are infected when they lick or eat them. If your dog drinks or forages around outside they could be at risk. 

Lungworms can cause severe and potentially fatal respiratory disease which is why we take them so seriously and recommend monthly treatment for all dogs.  Cats are not affected. You won't be able to see Lungworms as they migrate around the body through the tissue. 

The incidence of Lungworm varies across the country, but unfortunately in Bristol Lungworm is a common problem.


These worms feed on the pet's blood by hooking into the inner surface of the small intestine. They are around 1 cm in length, extremely thin and almost invisible to the human eye. Soon after feeding, the adult hookworm begins laying eggs which are then passed into the environment through the pet's faeces.

Unlike some parasites, hookworm larvae can live in the environment, thriving in moist areas such as grass, and can be picked up by the pet as they pass by.

Hookworms are extremely common in foxes (it is estimated that around 7 out of 10 have them) which means that with the growth of foxes in urban areas, hookworm also become more likely.

Puppies and kittens can be born with hookworms or become infected through their mother's milk.


Whipworms also feed on the pet's blood and are called whipworms because they have a larger head and a whip-like thin tail section. They are found mainly in young dogs (whose immunity tends to be lower) and, unlike hookworms, infection is only caused by swallowing the eggs.

The eggs can live in the soil for years and are picked up by the pet on paws, fur, toys, water dishes etc. Within 1 to 3 months after the egg is swallowed it hatches in the intestine, attaches to the intestine wall and begins sucking blood and laying eggs.

Please contact your branch surgery for more information or to book an appointment for a health check.

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